Later plague epidemics in London, England spread more rapidly than earlier epidemics, a study finds. Plague outbreaks during the second pandemic spanning the 14th to 19th centuries decimated human populations in Europe and Asia. Although genetic studies of the causative pathogen, Yersinia pestis, have yielded important insights, several aspects of the disease transmission mode and dynamics remain unclear. David Earn and colleagues analyzed historical, demographic, and epidemiological data from London, England and estimated mortality using three datasets assembled between 1348 and 1666. The archival records included the London Bills of Mortality, parish registers, and wills and testaments. The data revealed that the epidemic growth rate increased by a factor of four from the Black Death of 1348 to later epidemics, ending with the Great Plague of 1665. Additional analyses of mortality rates suggest that the 14th-century epidemics, and possibly later epidemics, likely did not spread primarily through direct, or pneumonic, human-to-human, transmission. Instead, the growth rates for both the early and late epidemics are consistent with bubonic, or indirect, flea-driven, transmission. In addition, climatic changes such as cooling temperatures and the substantial increase in human population density during the 300-year period may have contributed to the increase in the plague epidemic growth rate, according to the authors.
Article #20-04904: "Acceleration of plague outbreaks in the second pandemic," by David J.D. Earn, Junling Ma, Hendrik Poinar, Jonathan Dushoff, and Benjamin M. Bolker.
MEDIA CONTACT: David Earn, McMaster University, Hamilton, CANADA; tel: 905-962-8128; e-mail: earn@math.mcmaster.ca
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Journal
Proceedings of the National Academy of Sciences